As shown in FIG. 6 for example, a steel automotive wheel a of a two-piece type is known in which a generally disc-like wheel disc c is fitted inside a generally cylindrical wheel rim b and the wheel disc and the wheel rim are welded to each other to form one wheel. An example of the steel automotive wheel is proposed in JP-A-Hei 01-106701 (“JP '701”), for example. The wheel disc c includes a hub mounting section f that is coupled to a hub of an axle, a hat section h that is disposed on a back side of the hub mounting section f and protrudes to a surface side, and a disc flange d that is fitted inside the wheel rim b, which are circumferentially formed in a concentric pattern. The hub mounting section f and the hat section h is continuously formed through a hub surface rounded section j. The hat section h includes a hat top surrounding section p that protrudes to the surface side and a hat inner inclined surrounding section g that is continuously formed with the hat top surrounding section p and the hub surface rounded section j, which are circumferentially formed in a concentric pattern. A bulge section of the hat inner inclined surrounding section g includes an inner convex surrounding section k that protrudes to the surface side, which is circumferentially formed in a concentric pattern.
Because the wheel disc c of such the automotive wheel a can provide desired rigidity with the hat section h, the automotive wheel a has a high degree of effectiveness of preventing the deformation produced by various loads acting in the travel of the automobile and can provide high strength in general. Specifically, when the lateral acceleration is applied during the travel of the automobile, relatively large bending moment is acted so as to bend the wheel disc c in a front-and-back side direction. Because the hat section h can provide high rigidity to prevent the deformation against the bending moment, high strength can be provided, and also excellent driving stability can be provided.
The inner convex surrounding section k that is provided in the hat inner inclined surrounding section g of the hat section h is one of parts that are formed over a circumferential direction facing a surface-side angular edge of a brake caliper mounted on the vehicle body so as not to contact with the brake caliper when the automotive wheel a is mounted on the automobile.